Search results for "meson"
showing 10 items of 1548 documents
Meson dominance of hadron form factors and large-Ncphenomenology
2012
We discuss the pion and nucleon form factors and generalized form factors within the large-Nc approach in the space-like region. We estimate their theoretical uncertainties through the use of the half-width rule, amounting to taking the half-width of the resonances as the deviation of their mass parameters. The approach embodies the meson dominance of form factors and the high-energy constraints from perturbative QCD. We compare the results with the available experimental data and lattice simulations. The meson-dominance form factors are generally comparable to the available experimental data within the half-width-rule uncertainties. Our errors are comparable to the experimental uncertainti…
The hadronic off-shell width of meson resonances
2000
6 páginas, 4 figuras.-- PACS number(s): 12.39.Fe, 12.38.Aw, 12.38.Cy, 12.40.Vv
Determination of the pole and MS¯ masses of the top quark from the tt¯ cross section
2011
We use higher-order quantum chromodynamics calculations to extract the mass of the top quark from the ttbar cross section measured in the lepton+jets channel in ppbar collisions at sqrt(s)=1.96 TeV using 5.3 fb-1 of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider. The extracted top quark pole mass and MSbar mass are compared to the current Tevatron average top quark mass obtained from direct measurements.
Including Tetraquark Operators in the Low-Lying Scalar Meson Sectors in Lattice QCD
2019
Lattice QCD allows us to probe the low-lying hadron spectrum in finite-volume using a basis of single- and multi-hadron interpolating operators. Here we examine the effect of including tetraquark operators on the spectrum in the scalar meson sectors containing the $K_0^*(700)$ ($\kappa$) and the $a_0(980)$ in $N_f = 2 + 1$ QCD, with $m_\pi \approx 230$ MeV. Preliminary results of additional finite-volume states found using tetraquark operators are shown, and possible implications of these states are discussed.
Measurement of theB→πlνBranching Fraction and Determination of|Vub|with TaggedBMesons
2006
We report a measurement of the B ->pi center dot nu branching fraction based on 211 fb(-1) of data collected with the BABAR detector. We use samples of B-0 and B+ mesons tagged by a second B meson reconstructed in a semileptonic or hadronic decay and combine the results assuming isospin symmetry to obtain B(B-0 ->pi(-)center dot(+)nu)=(1.33 +/- 0.17(stat)+/- 0.11(syst))x10(-4). We determine the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-ub vertical bar by combining the partial branching fractions measured in ranges of the momentum transfer squared and theoretical calculations of the form factor. Using a recent lattice QCD calculation, we find vertical bar V-ub …
Alternative large-n limit for QCD and its implications for low-energy nuclear phenomena
1990
The Corrigan-Ramond model for large-{ital N} QCD is analyzed in detail. The spectrum, leading-order results for interactions, and an effective Lagrangian describing large-{ital N} interactions are derived. This Lagrangian, when quantized, provides an effective quantum field theory for mesons and baryons. The applicability of such a theory to low-energy nuclear phenomena is studied. The model has features that distinguish it clearly from standard large-{ital N} QCD.
Charge transport and vector meson dissociation across the thermal phase transition in lattice QCD with two light quark flavors
2015
We compute and analyze correlation functions in the isovector vector channel at vanishing spatial momentum across the deconfinement phase transition in lattice QCD. The simulations are carried out at temperatures $T/T_c=0.156, 0.8, 1.0, 1.25$ and $1.67$ with $T_c\simeq203$MeV for two flavors of Wilson-Clover fermions with a zero-temperature pion mass of $\simeq270$MeV. Exploiting exact sum rules and applying a phenomenologically motivated ansatz allows us to determine the spectral function $\rho(\omega,T)$ via a fit to the lattice correlation function data. From these results we estimate the electrical conductivity across the deconfinement phase transition via a Kubo formula and find eviden…
Pseudoscalar transition form factors: (g − 2) of the muon, pseudoscalar decays into lepton pairs, and the η – η′ mixing
2015
We present our model-independent and data-driven method to describe pseudoscalar meson transition form factors in the space- and (low-energy) time-like regions. The method is general and conforms a toolkit applicable to any other form factor, of one and two variables, with the potential to include both high- and low-energy QCD constraints altogether. The method makes use of analyticity and unitary properties of form factors, it is simple, systematic and can be improved upon by including new data. In the present discussion, the method is used to show the impact of experimental data for precision calculations in the low-energy sector of the Standard Model. In particular, due to its relevance …
Rho meson properties in the chiral theory framework
2002
13 páginas, 7 figuras, 1 tabla.-- arXiv:hep-ph/0208199v1
A new approach to the ϱ-meson in QCD
1993
We examine whether strict local duality between the asymptotic and the resonance region, which is of course believed to be valid in QCD, already appears at the present stage of QCD calculations. For this purpose we propose a new method of stable analytic extrapolation which follows the spirit of a previously used method but has essential advantages compared to the original formulation. A careful analysis of the present QCD ϱ-amplitude leads indeed to a prominent bump structure in the resonance region. This is a first evidence for the validity of strictly local duality within QCD.